Portable liquid heater



Nov. 2, 1948.

H. B. HOLTHOUSE" PORTABLE LIQUID HEATER Filed July 17, 1943 fzuenz'orx- Hang/,5 Half/2011,33

Patented Nov. 2, 1948 PORTABLE LIQUID HEATER Harry 'B. Holthouse, Chicago, Ill., assignor to Motorola, Inc., a corporation of Illinois Application July 17, 1943, Serial No. 495,152

1 Claim. 1

The present invention relates to portable selfcontained liquid heaters and has for one of its objects the provision of an improved and completely self-contained liquid heater which may be used either as a portable source of hot liquid or as a unit for sterilizing surgical instruments or the like.

It is another object of the invention to provide a portable liquid heater of the internal combustion type which utilizes electrical equipment ex clusively in the delivery of liquid fuel to the combustion. chamber and in producing efficient combustion of the liquid fuel within the combustion chamber.

According to another object of the invention, all parts of the heating unit, including the fuel reservoir, are housed within the container in which the liquid heating chamber is provided.

In accordance with still another object of the invention, the parts of the structure are so arranged that the liquid to be heated is circulated in direct contact with the Walls of the combustion chamber to provide for maximum efiiciency in the transfer of heat energy from the heated gases of the combustion chamber to the liquid.

In accordance with still another object of the invention, facilities are provided forreadily converting the heater from an open top liquid vat suitable for use in the cleaning and sterilizing of instruments or the like, into a closed unit having a sealed liquid chamber which is adapted for transportation from one point to another without spilling the contents of the chamber.

It is a still further object of the invention to provide a portable liquid heating unit of the character described which is simple in arrangementfrugged in construction, is comprised of a minimum number of parts, and is adapted for efficient operation over a prolonged service life with a minimum of servicing.

The invention, both as to its organization and method of operation, together with further ob jects and advantages thereof, will best be understood by reference to the following specification taken. in connection with the accompanying drawings, in which:

Fig. l is a corner perspective view illustrating a portable liquid heater characterized by the features of the present invention;

Fig. 2 is a fragmentary longitudinal sectional view of certain of the parts provided in the heater shown in Fig. 1;

Fig. 3 is a transverse sectional view of the "heater shown in Fig. 2; and

Fig. 4 is a fragmentary sectional View illustrating in developed form the structure of the combustion chamber forming a part of the heater shown in Figs. 2 and 3.

Referring to the drawings and more particularly to Figs. 1 and 2 thereof, the improved portable liquid heater there illustrated comprises an open top container ill of substantially rectangular cross section. The container is provided with four corner feet l2 which serve to maintain the lower edge surfaces of the container structure above the floor or other surface upon which the heater is supported. The open top of the container l0 may be closed by a cover M, which is hinged to the upper edge of the container wall and may be brought into clamping engagement with the upper edge of the container by means of two fasteners E5 of the toggle type. These fasteners include base parts respectively mounted upon adjacent surfaces of the cover it and the container H). A strap is having its ends suitably anchored at two spaced-apart points upon the cover M is provided to facilitate handling of the heater during transportation thereof.

A liquid chamber is formed within the container ID by providing a partition wall l3 which extends between the four side walls of the con tainer intermediate the open top thereof and the base. This partition wall is line welded at its edges to the inner wall surfaces of the container 10 to provide leakproof connections therebetween. Adjacent the bottom of the liquid container thus formed above the partition wall it, a suitable manuall operable faucet 28 is provided for permitting heated liquid to be withdrawn from the chamber.

From the above explanation it will be understood that the partition wall .l3 in combination with the lower portions of the container side wall, forms a compartment within which certain portions of the heater unit may be mounted. More specifically, a fuel reservoir in the form of a tank 2! is provided within this compartment. The tank 2i is rigidly mounted in this position, and is provided with a fuel inlet neck 22 which extends through an opening in the partition wall 13 and is threaded to receive a cover cap 23. In order to gain access to the neck 22, the end wall of the container is provided with an opening 24 through which the cap 23 may be removed and the spout of a fuel container inserted within the neck 22 for the purpose of filling the tank 2E. The opening 24 and the neck 22 are closed off from the liquid chamber of the container by means of a housing structure 25, the edges of which are line welded to the container end wall 3 and the partition wall 13 to provide liquid tight connections therebetween.

Briefly considered, the heating unit as provided in the portable heater comprises a heating structure 26 which is disposed within the lower compartment of the container l8 and has a combustion chamber formed therewithin, a fuel conditioning unit 27, an electrically operated fuel pump 28 for delivering fuel from the tank 2! to the fuel conditioning unit 27, and air moving means in the form of a fan 29 which is driven by an electric motor 39 to supply combustion air to the fuel conditioning unit 27 and thecombustion chamber formed within the heating structure 26. More specifically considered, the structure 26 comprises a tubular body SI of unit construction which is provided with alternate peripheral sections 32 and radially extending fin elements 33. The fin elements 33 are bent double so that their inner ends are open to the bore or space within the tubular member 31. This member is divided axially into four interconnected passages 35a, 34b, 34c and 3412 by means of a substantially X-shaped partition member 35. The side portions of the partition member 35 are fitted within the upper open ends of certain of the fin elements 33 and are welded therein to provide a rigid assembly. The right end of the combustion chamber as viewed in Fig. 2 of the drawings is closed by means of a plate 36 which is seam welded to the adjacent edge portions of the tubular member 31 to seal the end of this member. At its left end, the tubular member 3| is sealed by the inner wall portion 37a of a housing shell 37. This shell completely covers the open end of the tubular member SI and the end openings into the fins 33, and is seam welded to the edge surfaces of the tubular member 3i to seal the left end of this member.

The fan and motor assembly is supported from the partition wall I3 in the compartment defined at the lower side of this wall by the side walls of the container It. More specifically, the motor 30 is mounted upon the underside of the partition wall l3 by means of two bracket pieces 39 and 49, and the motor shaft is extended within the housing shell 31 to have the fan 29 rigidly mounted thereon through an opening 4! which also serves as an air admission port to the pressure chamber. The electrically operated fuel pump 28 is mounted on the container in by means of a bracket piece 42. This pump is of the electromagnetic actuated type and may be of any desired commercial construction. thereof is connected to the fuel reservoir by means of an inlet tube 3 which is sealed within an opening provided through the end wall of the tank 2! and includes a downwardly extending neck which opens at a point adjacent the bottom of the tank. The outlet of the pump 28 is connected to the air conditioning unit 27 to provide fuel therefor. The conditioning unit 2! may include a heating coil for conditioning fuel and air for burning.

Operation of the heating unit may be initiated by supplying current to the motor 35, the operating winding of the pump 28 and the heating element of the unit 21. The resulting operation of the motor driven fan 29 causes air to be sucked into the pressure chamber within the shell 3'! beneath the lower edges of the container [8 and through the opening 4!. As a result, the pressure of the air confined within the shell 31 is increased above atmospheric pressure so that The inlet side air is forced into the fuel conditioning unit 21. Incident to the operation of the pump 28, fuel is withdrawn from the tank 2| through the conduit 43 and delivered to the conditioning unit 21. Combustion of the gases continues throughout the four connected passages 34' of the combustion chamber so that heat energy is radiated through the walls and fins of the tubular member 3|. The completely burned combustion gases are finally exhausted through the member 62.

For heating the water in the liquid compartment from the heating unit, a casing 56 is provided about the tubular member 31. The fins 33a and 332) are alternately staggered and extend inwardly from opposite ends of the tubular member 3i and each stopping short of the opposite end toward which it extends. The inner ends of the fins 33a and 332) are pinched together and welded in the manner shown in Fig. 4 to prevent liquid held within the walls of the container ill from entering the combustion chamber. The outer radial edges of the fins 33a and 33?; are enclosed by a casing 65, the ends of which are seam welded to the adjacent surfaces of the end plate 3% and the housing end wall 37a. Also, the outwardly radial edge of each fin is suitably joined to the inner surface of the casing 6t so that a sinuous liquid circulating path is provided within the casing at the outer side of the combustion chamber. At the side of the member 3! which is disposed directly beneath the partition wall 13, this member is provided with a reversely bent fin 330, which extends throughout the length of the member 3! and is joined at its ends to the closing plate 38 and the end wall 37a of the housing shell 3?. On either side of this particular fin, conduits are provided which communicate with the liquid chamber formed within the side walls of the container 10 above the partition wall l3. More specifically, an inlet conduit 85 is provided for connecting the liquid chamber with the passage 63 disposed to the right of the fin 33c, as viewed in Fig. 3 of the drawings. This conduit is connected to the passage 68 through an opening in the casing G5 and extends through an opening provided in the partition wall l3 so that the inlet end thereof is substantially fiush with the upper surface of the par tition wall. The passage 69 disposed on the opposite side of the fin 33c is in fluid communication with the liquid chamber through an outlet conduit 67 which projects upwardly into the liquid chamber through a second opening in the partition wall I3 and communicates with the passage 69 through an opening in the casing 65. It will be understood in this regard that suitable provisions are made for providing watertight connections between the casing 65, the partition wall l3 and the two conduits 65 and 61, in order to prevent leakage of the liquid held within the liquid chamber of the container It.

In the operation of the heater, liquid held within the liquid chamber of the container ill enters the casing 66 through the inlet conduit 65. Due to the presence of the fins 33a and 33b arranged in staggered relationship within the casing 56, the liquid follows a sinuous path through the chamber defined between the casing 65 and the tubular member 3: until it is returned to the liquid chamber through the passage 69 and the connected outlet conduit 67. In this regard it will be understood that thermally induced flow of the liquid through the sinuous path defined by the fins 33 within the casing 86 is produced during operation of the heater. It will also be understood that the eembllstion chamber of the heater is substantially entirely surrounded by the liquid to be heated with the result that the efiiciency of heat transfer is relatively high. Further, by providing all elements of the heating unit within the compartment formed beneath the partition wall 13 of the container, the volumetric capacity of the liquid chamber for a heater of given size is substantially increased.

While one embodiment of the invention has been disclosed, it will be understood that various modifications may be made therein, which are Within the true spirit and scope of the invention.

I claim.

A self-contained portable liquid heater comprising a container provided with a liquid chamber, a partition wall extending between the side walls of said container to act as the bottom wall of said liquid chamber and to define a compartment beneath said wall, a heating unit disposed in said compartment and provided with means defining a combustion chamber having a tubular outer wall, a fuel reservoir disposed in said compartment, said heating unit including means in said compartment for delivering fuel from said reservoir and air for combustion to said combustion chamber, a jacket enclosing said tubular wall to define therewith a sealed liquid heating chamber, inlet and outlet conduits extending through said partition wall, said conduits having open ends communicating with said liquid chamber and opposite open ends communicating with said liquid heating chamber, a partition wall extending through said liquid heating chamber between said opposite ends of said conduits to provide for circulation of the liquid from said inlet conduit through said heating chamber to said outlet conduit, and staggered heat radiating fins alternately extending inwardly from opposite ends of said heating chamber to cause the liquid circulating through said heating chamber to follow a sinuous path.

HARRY B. HOLTHOUSE.

REFERENCES CITED The following references are of record in the file of this patent: 4

5 UNITED STATES PATENTS Number Name Date 548,679 Victor Oct. 29, 1895 691,866 Laird Jan. 28, 1902 724,547 Cooke 1 Apr. 7, 1903 814,578 Walter Mar. 6, 1906 971,735 Edwards Oct. 4, 1910 1,058,601 Knittel Apr. 8, 1913 1,523,436 McIntyre Jan. 20, 1925 1,756,787 Goughnour Apr. 29, 1930 1,801,888 Teeple Apr, 21, 1931 1,923,614 Clarkson Aug. 22, 1933 1,953,578 Rice Nov. 14, 1933 1,986,914 Avery Jan. 8, 19.35 2,068,692 Myron Jan. 26, 1937 2,126,657 Petersen Aug. 9, 1938 2,162,571 Bock June 13, 1939' 2,190,165 Shurts Feb. 13, 1940 2,264,226 Toner Nov. 25, 1941 2,286,854 Holthouse June 16, 1942 2,286,856 Holthouse June 16, 1942 2,286,857 Holthouse, Jr June 16, 1942 2,362,259 Findley Nov. 7, 1944 FOREIGN PATENTS Number Country Date 5,823 Germany June 27, 1879 10,638 Australia Dec. 21, 1932 17,964 Great Britain 1911 212,714 Germany Aug. 7, 1909 332,575 Great Britain July 23, 1930 820,076 France July 19, 1937 

